融化夹层厚度影响因素分析与片块石路基降温效果研究

Study of the factors influencing the thickness of residual thawed interlayers and cooling effect of block-stone embankment

青藏公路沿线存在大量融化夹层,常年不冻的融化夹层会使路基出现沉陷、波浪等病害,严重威胁道路的安全运营.通过对昆仑山垭口南至五道梁的地质勘探资料和地温观测数据进行分析,研究了融化夹层厚度与年平均地温、路基高度的关系,发现融化夹层厚度随年平均地温的升高而增大,随路基高度的升高呈先减小后增大的趋势.根据以上研究,提出片块石路基对融化夹层进行处治,保护路基下伏多年冻土,并通过五道梁段片块石路基试验工程进行验证.通过对地温观测数据分析,发现片块石路基能很好的消除融化夹层,在同一深度处片块石路基地温明显低于普通路基,很好的保护了下伏多年冻土.

There exists a great amount of residual thawed interlayers along the Qinghai-Tibet Highway （QTH）. The unfrozen residual thawed interlayers would result in embankment diseases, such as thaw settlement and wave etc. , which exert threat on the highway safety. In this study, based on the drilled information and monitored ground temperature data from Kunlunshan-Wudaoliang section along the QTH, the relationship between the thickness of residual thawed interlayers and mean annual ground temperature and embankment height were ana- lyzed. It is found that the thickness of residual thawed interlayers increases with mean annual ground tempera- ture, and decreases first and then increases with embankment height increasing. Block-stone embankment can help to protect the permafrost beneath it and to decrease the residual thawed interlayers. In order to prove the effect of block-stone embankment, some experiments of block-stone embankment were conducted in Wudaoliang section along the QTH. According to the monitored ground temperature data, the residual thawed interlayers will gradually disappear after the block-stone embankment constructed. Thus, block-stone embankment is proved to be effective in protecting the permafrost under an embankment in cold regions.